In power generation, turbine blades are subjected to a demanding range of performance requirements including withstanding high temperatures and temperature fluctuations, high pressures, high speed rotation, vibrational loading/stress, metal fatigue, irregular part geometry, and nearly uninterrupted turbine engine usage. Coincidentally, auxiliary blade components, such as blade snubbers, are also challenged to endure these extreme operating conditions.
In turbine engines snubbers are provided as an interface between pairs of blades and help to minimize the vibrational loading and stresses experienced by the blades. Snubbers provide additional stiffness to the blades which in turn impacts the blade design options—such as allowing for reduced axial blade width or optimization of the blade frequency response. Snubbers are designed and selected to function in the extremely demanding operating environment of the turbine blade.
Typical methods of forming and joining machine parts presents limitations constraining the use of these techniques in forming snubbers and in integrating snubbers with turbine blades. For example, some methods require excavating portions of the turbine blade before adding on material used to construct a snubber. These excavated areas present modifications to the original blade design which range from changing the overall aerodynamics of the blade to introducing reductions in the structural integrity of the blade.
Other methods of forming and joining machine parts involve subjecting the blade and snubber to high temperatures, such as via the use of a welding process, which consequentially, may alter the physical characteristics of the blade.
Since, overall, snubbers are used to enhance turbine engine performance, there is a need optimize both the design of the snubber, the composition of the snubber, as well as the techniques used to attach the snubber onto the turbine blade.